Effects of Roasting Cotton Seed on its Gossypol Content, Ruminal Degradability and in Vitro Protein Digestibility

Subject Areas : Journal of Crop Ecophysiology

M.  Taghinejad Roudbaneh ¹ (Assistant Prof., Department of Animal Nutrition, Faculty of Agriculture, Islamic Azad University, Tabriz Branch, Tabriz, Iran)
S.R.  Ebrahimi ² (Assistant Prof., Department of Animal Nutrition, Faculty of Agriculture, Islamic Azad University, Shahr-e-Qods Branch, Shahr-e-Qods, Iran)

Received: 2010-01-30 Accepted : 2010-08-16 Published : 2010-05-22

Keywords: electrophoresis, Cotton seed, Gossypol, Nylon bag techniques, Ruminal degradability and Roasting,

Abstract :

This research was conducted to evaluate the effects of cotton seed roasting (125°C for 15 and 30 minutes) on its gossypol content, chemical composition, in vitro CP digestibility, ruminal dry matter (DM) and crud protein (CP) degradability. Degradation kinetics of DM and CP were determined according to in situ procedure with three ruminally fistulated Taleshi bulls. Roasting cotton seed had no effect on chemical composition of feed samples (P>0.05; roasting at 125°C for 15 and 30 minute decreased free gossypol by 17.5 and 21.3%, respectively (P<0.05). Although, roasting at 125°C for up to 15 and 30 minute decreased the degradation rate of CP (P<0.05) but it had no effect on effective rumen protein degradability of roasted cottonseed compared to untreated cottonseed (P<0.05). Electrophoresis results indicated that roasting at 125°C for 15 and 30 minute did not alter the disappearance pattern of protein subunits in cottonseed. The result showed that, although roasting decreased the free gossypol content of cottonseed but it was not effective at decreasing its effective rumen protein degradability.